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Livestock-carrying capacity and overgrazing status of alpine grassland in the three-river headwaters region, China

Journal of Geographical Sciences 2014年第2期24卷 303-312页

作者： ZHANG Jiping ZHANG Linbo LIU Welling QI Yue WO Xiao Chinese Research Academy of Environmental Sciences Beijing 100012 China State Environmental Protection Key Laboratory of regional Ecological Processes and Functions Assess-ment Beijing 100012 China East China Institute of Technology Faculty of Geomatics Nanchang 330012 China

The three-river headwaters region in China is an ecological barrier providing en- vironmental protection and regional sustainable development for the mid-stream and down- stream areas, which also plays an important role in animal husbandry in China. This study estimated the grassland yield in the three-river headwaters region based on MODIS NPP data, and calculated the proper livestock-carrying capacity of the grassland. We analyzed the overgrazing number and its spatial distribution characteristics through data comparison be- tween actual and proper livestock-carrying capacity. The results showed the following：（1） total grassland yield （hay） in the three-river headwaters region was 10.96 million tons in 2010 with an average grassland yield of 465.70 kg/hm2 （the spatial distribution presents a decreasing trend from the east and southeast to the west and northwest in turn）; （2） the proper livestock-carrying capacity in the three-river headwaters region is 12.19 million sheep units （hereafter described as ＂SU＂）, and the average stocking capacity is 51.27 SU [the proper carrying capacity is above 100 SU/km2 in the eastern counties, 60 SU/km2 in the cen- tral counties （except Madoi County）, and 30 SU/km2 in the western counties]; and （3） total overgrazing number was 6.52 million SU in the three-river headwaters region in 2010, with an average overgrazing ratio of 67.88% and an average overgrazing number of 27.43 SU/km2 A higher overgrazing ratio occurred in Tongde, Xinghai, Yushu, Henan and Z^kog. There was no overgrazing in Zhiduo, Tanggula Township and Darlag, Qumerleb and Madoi. The re- mainder of the counties had varying degrees of overgrazing.

关键词： proper livestock-carrying capacity actual livestock-carrying capacity overgrazing number three-river headwaters region

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Assessing the effects of vegetation and precipitation on soil erosion in the three-river headwaters region of the Qinghai-Tibet Plateau,China

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Journal of Arid Land 2020年第5期12卷 865-886页

作者： HE Qian DAI Xiao'ai CHEN Shiqi College of Earth Science Chengdu University of TechnologyChengdu 610059China College of Foreign Languages and Cultures Chengdu University of TechnologyChengdu 610059China

Soil erosion in the three-river headwaters region(TRHR)of the Qinghai-Tibet Plateau in China has a significant impact on local economic development and ecological *** and precipitation are considered to be the main factors for the variation in soil ***,it is a big challenge to analyze the impacts of precipitation and vegetation respectively as well as their combined effects on soil erosion from the pixel *** assess the influences of vegetation and precipitation on the variation of soil erosion from 2005 to 2015,we employed the Revised Universal Soil Loss Equation(RUSLE)model to evaluate soil erosion in the TRHR,and then developed a method using the Logarithmic Mean Divisia Index model(LMDI)which can exponentially decompose the influencing factors,to calculate the contribution values of the vegetation cover factor(C factor)and the rainfall erosivity factor(R factor)to the variation of soil erosion from the pixel *** general,soil erosion in the TRHR was alleviated from 2005 to 2015,of which about 54.95%of the area where soil erosion decreased was caused by the combined effects of the C factor and the R factor,and 41.31%was caused by the change in the R *** were relatively few areas with increased soil erosion modulus,of which 64.10%of the area where soil erosion increased was caused by the change in the C factor,and 23.88%was caused by the combined effects of the C factor and the R ***,the combined effects of the C factor and the R factor were regarded as the main driving force for the decrease of soil erosion,while the C factor was the dominant factor for the increase of soil *** area with decreased soil erosion caused by the C factor(12.10×10^3 km^2)was larger than the area with increased soil erosion caused by the C factor(8.30×10^3 km^2),which indicated that vegetation had a positive effect on soil *** study generally put forward a new method for quantitative assessment of the impacts

关键词： soil erosion vegetation cover rainfall erosivity Logarithmic Mean Divisia Index quantitative assessment three-river headwaters region

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Ecosystem changes revealed by land cover in the three-river headwaters region of Qinghai,China(1990–2015)

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Research in Cold and Arid regions 2023年第2期15卷 85-91页

作者： XuWei Sun Sen Li XiaoHui Zhai XiaoXu Wei ChangZhen Yan Gansu Academy of Eco-environmental Sciences LanzhouGansu 730020China Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China College of Social Development and Public Administration Northwest Normal UniversityLanzhouGansu 730070China

The three-river headwaters region(TRHR) of Qinghai Province, in the Tibetan Plateau of China, is the main source of the Yangtze, Yellow, and Lancang rivers, and is very significant to the security of freshwater resources for China and southeastern Asia. It is a critical ecological region of China for its ecological functions, and has been changed or even degraded in recent decades owing to climate change and human pressure. To effectively protect and restore the degraded ecosystems, the Chinese government initiated a series of ecological conservation projects in TRHR. It is essential to quantitatively assess ecosystem changes and their relationship to driving factors for indepth understanding of long-term changes of ecosystems and effects of ecological restoration policies and offer practical insights for ecological restoration. Here, land cover data has been interpreted with the series data of Landsat during 1990–2015. The patterns of different ecosystems and their developing process have been derived from land cover change. The results show that ecosystem types in TRHR include forest, grassland, cropland,wetland, artificial surface and barren land, accounting for 4.51%, 70.80%, 0.15%, 9.47%, 0.16% and 14.90%,respectively. Barren land converted to wetland was the significant ecosystem change from 1990 to 2015. Increases in temperature and precipitation and implementation of ecological rehabilitation helped maintain relatively stable ecosystem patterns. It is necessary to continue ecological projects to improve and/or maintain the ecosystems in TRHR because there is still a risk of land degradation under increasing climate change and human activity.

关键词： three-river headwaters region Ecosystem change Land cover Affecting factor

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Increased southerly and easterly water vapor transport contributed to the dry-to-wet transition of summer precipitation over the three-river headwaters in the Tibetan Plateau

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气候变化研究进展:英文版 2023年第4期14卷 502-510页

作者： Xuan LIU Ming-Xiang YANG Ning-Peng DONG Wei-Ning XIE Hong-Gang LI Zhen GUAN Fan WEN Hao WANG Deliang CHEN College of Civil Engineering Tianjin UniversityTianjin 300354China State Key Laboratory of Simulation and Regulation of Water Cycle in river Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Cooperative Innovation Center for Water Safety&Hydro Science Hohai UniversityNanjing 210098China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098China Hydrology and Water Resources Survey Bureau of Hainan Province Hainan 571126China Huaneng Lancang river Hydropower INC. Kunming 650214China regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg S-40530Sweden

The three-river headwaters(TRH)region in the Tibetan Plateau is vulnerable to climate change;changes in summer(June–August)precipitation have a significant impact on water security and sustainability in both local and downstream ***,the changes in summer precipitation of different intensities over the TRH region,along with their influencing factors,remain *** this study,we used observational and ERA5 reanalysis data and employed a precipitation categorization and water vapor budget analysis to quantify the categorized precipitation variations and investigate their possible linkages with the water vapor *** results showed an increasing trend in summer precipitation at a rate of 0.9 per year(pregion(158.2%),while southeasterly water vapor transport through the eastern boundary was responsible for the increased net water vapor flux in the central TRH(155.2%)and eastern TRH(229.2%)***,we inferred that the dry-to-wet transition of summer precipitation and the increased‘very heavy precipitation’over the TRH was caused by increased easterly and southerly water vapor transport.

关键词： Summer precipitation three-river headwaters region Precipitation intensity Water vapor budget

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